US20160202417A1 - Reflective optical coherence tomography probe - Google Patents
Reflective optical coherence tomography probe Download PDFInfo
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- US20160202417A1 US20160202417A1 US14/989,261 US201614989261A US2016202417A1 US 20160202417 A1 US20160202417 A1 US 20160202417A1 US 201614989261 A US201614989261 A US 201614989261A US 2016202417 A1 US2016202417 A1 US 2016202417A1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
- A61B5/6852—Catheters
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/262—Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0062—Arrangements for scanning
- A61B5/0066—Optical coherence imaging
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
- A61B5/0084—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02034—Interferometers characterised by particularly shaped beams or wavefronts
- G01B9/02038—Shaping the wavefront, e.g. generating a spherical wavefront
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02049—Interferometers characterised by particular mechanical design details
- G01B9/0205—Interferometers characterised by particular mechanical design details of probe head
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/0209—Low-coherence interferometers
- G01B9/02091—Tomographic interferometers, e.g. based on optical coherence
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
- G02B6/3632—Mechanical coupling means for mounting fibres to supporting carriers characterised by the cross-sectional shape of the mechanical coupling means
- G02B6/3636—Mechanical coupling means for mounting fibres to supporting carriers characterised by the cross-sectional shape of the mechanical coupling means the mechanical coupling means being grooves
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
Definitions
- the present disclosure relates to optical coherence tomography, and in particular to a monolithic beam-shaping optical probe for an optical coherence tomography probe.
- OCT optical coherence tomography
- the core of an OCT system is a Michelson interferometer, which typically includes a first optical fiber which is used as a reference arm and a second optical fiber which is used as a sample arm.
- the sample arm includes the sample to be analyzed, as well as a probe that contains optical components therein.
- a light source upstream of the probe provides light used in imaging.
- a photodetector is arranged in the optical path downstream of the sample and reference arms. The probe is used to direct light into or onto the sample and then to collect scattered light from the sample.
- Optical interference of light from the sample arm and the reference arm is detected by the photodetector only when the optical path difference between the two arms is within the coherence length of the light from the light source.
- Depth information from the sample is acquired by axially varying the optical path length of the reference arm and detecting the interference between light from the reference arm and scattered light from the sample arm.
- a three-dimensional image is obtained by transversely scanning in two dimensions the optical path in the sample arm. The axial/depth resolution of the process is determined by the coherence length, while the overall transverse resolution is dictated by the size of the image spot formed by the optical components of the probe.
- the probe typically needs to be inserted into a small cavity of the body, it must be small and preferably have a simple optical design.
- Exemplary designs for the probe include a transparent cylinder in which the miniature probe optical components are contained and through which light is transmitted and received.
- light may be lost due to back reflection when it passes through materials having a different refractive index, thus decreasing image spot intensity. Additionally, back reflections decrease the signal to noise ratio in the data.
- having multiple and separate optical components in the probe is generally problematic because the small optical components have to be assembled and aligned, which adds to the cost and complexity of manufacturing the probe.
- a beam-shaping optical system suitable for use with optical coherence tomography includes a beam-shaping body having a beam-shaping element and an alignment feature.
- An optical fiber is coupled to the alignment feature.
- the fiber has a fiber end configured to emit an electromagnetic beam.
- the fiber and the body are configured to direct the beam into the beam-shaping element such that the beam is shaped into an image spot solely by reflection from the beam-shaping element.
- an optical coherence tomography probe includes a beam-shaping body integrally defining an alignment feature and a beam-shaping element, the beam-shaping element being an external surface of the beam-shaping body.
- An optical fiber is coupled to the alignment feature, the fiber having a fiber end configured to emit a beam.
- the fiber and the body are configured to direct the beam into the beam-shaping element such that the beam is shaped externally of the beam-shaping body.
- a method of forming an image spot for optical coherence tomography using an optical fiber includes steps of supporting an optical fiber in an alignment feature of a beam-shaping body having a beam-shaping element, transmitting an electromagnetic beam from the optical fiber into the beam-shaping element, and shaping the beam with the beam-shaping element solely by reflection into the image spot
- FIG. 1 is an elevated exploded view of an optical probe for use in OCT according to one embodiment
- FIG. 2A is a cross-sectional view of the optical probe depicted in FIG. 1 in assembly taken along line II-II according to one embodiment
- FIG. 2B is a cross-sectional view of the optical probe depicted in FIG. 1 in assembly taken along line II-II according to an alternative embodiment
- FIG. 3 is a schematic diagram of an OCT alignment system that includes the optical probe according to one embodiment.
- FIG. 4 is a schematic diagram of an OCT system that includes an optical probe according to one embodiment.
- the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivates thereof shall relate to an optical probe 10 as oriented in FIG. 1 , unless stated otherwise. However, it is to be understood that the optical probe 10 may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.
- the optical probe 10 includes a beam-shaping body 14 to which an optical fiber 18 may be coupled.
- the beam-shaping body 14 integrally defines an alignment feature 22 and a beam-shaping element 26 .
- the optical fiber 18 has a central axis 28 and includes a cladding 30 , a core 32 , and a coating 34 .
- the coating 34 is polymeric.
- a section of the coating 34 is stripped from the optical fiber 18 to form a coated portion 36 and an uncoated portion 38 .
- the uncoated portion 38 includes a fiber end 40 configured to emit an electromagnetic beam 42 .
- the electromagnetic beam 42 is emitted along an optical axis OA defined by the beam-shaping body 14 .
- the optical fiber 18 is coupled to the alignment feature 22 .
- the beam-shaping body 14 is monolithic and integrally defines the beam-shaping element 26 and the alignment feature 22 .
- the beam-shaping body 14 includes a front end 44 , a back end 46 , and an external surface 48 .
- the beam-shaping body 14 is monolithic, for convenience, the beam-shaping body 14 can be considered to be three main sections, namely a front section 60 adjacent front end 44 and the beam-shaping element 26 , a central section 64 in between the front end 44 and back end 46 , and a back section 68 adjacent the back end 46 and the alignment feature 22 .
- the beam-shaping body 14 includes a polymeric composition.
- Exemplary polymeric materials for the beam-shaping body 14 include ZEONOR® (available from Zeon Chemicals L.P., Louisville, Ky.), polyetherimide (PEI), polyethylene, polypropylene, polycarbonate, engineered polymers (e.g., liquid crystal), as well as any other polymeric material or combination of polymeric materials capable of forming the beam-shaping body 14 and producing a smooth surface.
- the beam-shaping body 14 may include metals, ceramics, or composites thereof.
- the beam-shaping body 14 is capable of formation by conventional manufacturing techniques such as injection molding, casting, machining, thermoforming, or extrusion.
- the external surface 48 of the back section 68 includes a first flat surface 72 and a second flat surface 76 , the alignment feature 22 integrally formed therein. While the beam-shaping body 14 is depicted with the first flat surface 72 elevated relative to the second flat surface 76 , various embodiments allow for the flat surfaces 72 , 76 to be planar (i.e., no offset). In other embodiments, the second flat surface 76 may be elevated above the first flat surface 72 .
- the alignment feature 22 includes a first v-shaped groove 80 located in the first flat surface 72 and a second v-shaped groove 84 located in the second flat surface 76 .
- the second v-shaped groove 84 is open to and aligned with the first v-shaped groove 80 .
- the alignment feature 22 may additionally or alternatively incorporate grooves or trenches which are generally circular, square, u-shaped or other shapes operable to couple with the optical fiber 18 .
- the first and second v-shaped grooves 80 , 84 have differing depths and pitches, with the first v-shaped groove 80 having a greater depth and higher pitch than the second v-shaped groove 84 .
- the differing depths and pitches of the first and second v-shaped grooves 80 , 84 allow both the coated and uncoated portions 36 , 38 of the optical fiber 18 to be coupled to the beam-shaping body 14 while allowing the central axis 28 of the optical fiber 18 to align substantially coaxial with the optical axis OA of the beam-shaping body 14 . Additionally, the differing depths and pitches of the first and second v-shaped grooves 80 , 84 serve to define an alignment feature edge 88 between the first and second v-shaped grooves 80 , 84 against which the coated portion 36 of the optical fiber 18 butts when optical fiber 18 is coupled in the first and second v-shaped grooves 80 , 84 .
- the alignment feature edge 88 assists in properly aligning the optical fiber 18 with the beam-shaping body 14 and also serves to keep the optical fiber 18 in place within the first and second v-shaped grooves 80 , 84 .
- the alignment feature 22 may incorporate a stepped aperture allowing insertion of the optical fiber 18 into the beam-shaping body 14 , or other features, for joining the fiber 18 to the back section 68 of the body 14 .
- the central section 64 of the beam-shaping body 14 is thinner than the back section 68 and the front section 60 .
- the central section 64 of the exterior surface 48 defines a central surface 90 and an air gap 94 .
- the central surface 90 of the central section 64 extends beneath the optical axis OA of the beam-shaping body 14 between the front section 60 and the back section 68 .
- the air gap 94 allows the fiber end 40 of the optical fiber 18 to extend into the central section 64 above the central surface 90 ( FIG. 2A ).
- the beam-shaping element 26 is integrally defined by the front section 60 of the beam-shaping body 14 .
- the front section 60 of the beam-shaping body 14 extends in an upwardly and inwardly curved manner from the central surface 90 to define the beam-shaping element 26 .
- the beam-shaping element 26 is substantially conic in shape and curves inwardly toward the optical axis OA of the beam-shaping body 14 .
- the conic shape of the beam-shaping element 26 is defined by a radius of curvature along an X-axis and a Y-axis of the beam-shaping body 14 .
- the beam-shaping element 26 may have a radius of curvature along the X-axis that is the same or different than a radius of curvature in the Y-axis.
- the radius of curvature of the X- and Y-axes of the beam-shaping element 26 may have an absolute value of between about 0.5 millimeters and about 10 millimeters, and more specifically, about 1.0 millimeter to about 4.0 millimeters.
- the conic constant of the X- and Y-axes of the beam-shaping element 26 may independently range from about 1 to about ⁇ 2, and more specifically between about 0 and about ⁇ 1.
- the radii and conic constants of the curvature explained above describe the overall shape of the beam-shaping element 26 , and do not necessarily reflect local radii or conic constants of the beam-shaping element 26 .
- the radius of curvature of the X-axis and Y-axis of the beam-shaping element 26 may be adjusted independently in order to correct for any transparent housings or sheaths disposed around the optical probe 10 .
- the conic shape of the beam-shaping element 26 may be decentered along the Y- or Z-axes between about 0.01 millimeters and about 0.8 millimeters. Additionally, the conic shape of the beam-shaping element 26 may have a rotation between the Y- and Z-axes of between about 70° and 120°.
- the beam-shaping element 26 is configured to collect and shape (e.g., collimate, converge, and/or change the optical path of) through reflection the electromagnetic beam 42 ( FIG. 2A ) emitted from the optical fiber 26 , as explained in greater detail below.
- Reflective coating 100 Positioned on the beam-shaping element 26 is a reflective coating 100 .
- Reflective coating 100 may be a dielectric coating, a metal coating, or an enhanced metal coating.
- Exemplary metal coatings include silver, gold, aluminum, and other lustrous metals capable of reflecting the beam 42 .
- Dielectric materials may include SiO 2 , TiO 2 and combinations thereof.
- enhanced metal coatings may include a combination of one or more of the previously described metals and/or dielectrics.
- the reflective coating 100 may also include a capping layer to protect it from environmental conditions (e.g., water, oxygen, and/or sterilization procedures) as well as an adhesion layer to bond the reflective surface 100 to the beam-shaping body 14 .
- the reflective coating 100 is positioned on the beam-shaping element 26 such that the emitted beam 42 is reflected externally to the beam-shaping body 14 , and not within it.
- the optical fiber 18 is depicted as protruding from the back section 68 into the air gap 94 above the central surface 90 of the central section 64 .
- the optical fiber 18 is configured to act as a wave guide for electromagnetic radiation, specifically light at an operating wavelength ⁇ .
- the optical fiber 18 carries light from an upstream light source (not shown) to the fiber end 40 where the light is emitted as the electromagnetic beam 42 .
- the operating wavelength ⁇ includes an infrared wavelength such as one in the range from about 850 nanometers to about 1,600 nanometers, with exemplary operating wavelengths ⁇ being about 1300 nanometers and about 1560 nanometers.
- the optical fiber 18 and the alignment feature 22 of the beam-shaping body 14 are configured to couple such that the electromagnetic beam 42 is emitted from the fiber end 40 on an optical path OP that is both substantially coaxial with the optical axis OA of the beam-shaping body 14 , and directed toward the beam-shaping element 26 .
- the beam 42 is emitted from the fiber end 40 , it propagates through the air gap 94 and the diameter of the optical path OP widens with increasing distance from the fiber end 40 .
- a distance D 1 between the fiber end 40 and the reflective surface 100 is set based on a desired size of a beam spot 104 .
- the beam spot 104 is the area of light the beam 42 forms as it strikes the beam-shaping element 26 .
- the beam spot 104 grows in diameter with increasing distance from the fiber end 40 .
- the beam spot 104 In order for the beam-shaping element 26 to properly shape the beam 42 , the beam spot 104 must be have the proper diameter when contacting the reflective surface 100 (e.g., approximately half the diameter of the reflective surface 100 ). Accordingly, the fiber end 40 must be placed a predetermined distance from the beam-shaping element 26 for the beam 42 to be properly shaped.
- the distance D 1 between the fiber end 40 and the reflective surface 100 may range between about 0.2 millimeters and about 2.6 millimeters. In one embodiment, the distance D 1 is about 1.314 millimeters.
- the diameter of the beam spot 104 may range from about 200 microns to about 800 microns and more specifically, between about 400 microns to about 600 microns.
- the beam 42 As the beam 42 enters the beam-shaping element 26 , its optical path OP is folded by an angle ⁇ from reflection off of the reflective coating 100 .
- the angle ⁇ is approximately 90°, but in various embodiments can vary by greater than or less than 10° on either side of 90°.
- the radius of curvature and position of the beam-shaping element 26 determine both the angle ⁇ that the optical path OP of beam 42 will be folded by, and also a working distance D 2 to an image plane IMP where the beam 42 converges to form an image spot 110 . Accordingly, the emitted beam 42 is shaped into the image spot 110 solely by reflection from the beam-shaping element 26 .
- the beam-shaping body 14 has an axial length L 1 in the range from about 5.0 millimeters to about 10.0 millimeters
- back section 68 has a length along the optical axis OA in the range of about 2.0 millimeters to about 5.0 millimeters
- the central section 64 has a length of about 0.2 millimeters to about 2.3 millimeters.
- front section 60 has a length in the range from 0.5 millimeters to 2.0 millimeters.
- the beam-shaping body 14 has width W 1 at back section 68 that can be in the range from 0.3 millimeters to 1.0 millimeters, and has a width W 2 at front section 60 that can be in the range from 0.5 millimeters to 2.0 millimeters.
- W 1 at back section 68 that can be in the range from 0.3 millimeters to 1.0 millimeters
- W 2 at front section 60 can be in the range from 0.5 millimeters to 2.0 millimeters.
- the values for these parameters are exemplary and other values and ranges are possible, depending on the particular application.
- the fiber end 40 of the optical fiber 18 may be cleaved at an angle in order to prevent undesired back reflection of light into the fiber 18 .
- OCT is particularly sensitive to back reflections of light which have not been scattered off of a sample to be tested (i.e., reflections from the optical probe 10 or refractive surfaces along the optical path OP). The back reflected light may lead to distortion in the OCT image because of increased noise and artifacts. Cleaving the fiber end 40 at an angle minimizes the coupling of the back reflected light back into the optical fiber 18 .
- the fiber end 40 may be cleaved at an angle between about 0° to about 10°, and more particularly between about 6° to 9°.
- the alignment feature 22 may be angled with respect to the optical axis OA of the optical probe 10 in order to compensate for the cleaved fiber end 40 .
- the angled alignment feature 22 would keep the optical path OP of the beam 42 substantially coaxial with the optical axis OA of the optical probe 10 .
- the fiber end 40 may include an anti-reflection film to reduce the amount of reflected light absorbed by the optical fiber 18 .
- the anti-reflection film may include a single or multilayer dielectric material configured to cancel light reflected back to the optical probe 10 .
- the fiber end 40 of the optical fiber 18 may also be ball-terminated.
- ball-termination of the optical fiber 18 may be achieved by placing the fiber end 40 between a pair of arc electrodes.
- the arc electrodes melt the cladding 30 and core 32 of the optical fiber 18 .
- Surface tension of the melted optical fiber 18 forms a substantially spherical ball on the fiber end 40 which then cools and hardens.
- the electromagnetic beam 42 may be emitted from the ball-termination fiber end 40 .
- the ball-termination of the fiber end 40 may have a diameter of between about 100 microns to about 600 microns, and more specifically between about 200 microns to about 500 microns.
- ball-termination of the fiber end 40 of the optical fiber 18 prevents the collection of back reflected light, and thus minimizes distortion of OCT images.
- ball-termination of the fiber end 40 causes the optical path OP of the emitted beam 42 to diverge faster than the cleaved fiber end 40 as it propagates through the air gap 94 (i.e. the diameter of the beam spot 104 increases faster). Because the optical path OP diverges faster from the ball-terminated fiber end 40 , the desired beam spot 104 size may be achieved with a shorter distance D 1 between the fiber end 40 and the beam-shaping element 26 .
- the ball-terminated fiber end 40 of FIG. 2B may include an anti-reflection film.
- a first step of supporting an optical fiber 18 in an alignment feature 22 of a beam-shaping body 14 having a beam-shaping element 26 is performed.
- a step of transmitting an electromagnetic beam 42 from the optical fiber 18 into the beam-shaping element 26 is performed.
- a step of shaping the beam 42 with the beam-shaping element 26 solely by reflection into the image spot 110 is performed.
- the optical probe 10 is depicted in use within an OCT alignment system 150 .
- light traveling within the optical fiber 18 exits the fiber end 40 and is emitted as beam 42 along the optical axis OA.
- the optical path OP of the beam 42 diverges as it passes through the air gap 94 until it enters the beam-shaping element 26 and reflects from the reflective surface 100 .
- the curvature of the beam-shaping element 26 causes the light to converge uniformly to image point 110 due to the beam-shaping element 26 surface being conic.
- the beam 42 passes through a portion of a housing 158 which may act as a protective sheath for the optical probe 10 .
- the optical probe 10 may be used with the optical coherence tomography alignment system 150 without any housing or protective covering.
- the beam 42 As the beam 42 converges, it forms the image spot 110 at the image plane IMP.
- the working distance D 2 is measured between the horizontal portion of the optical axis OA of the probe and the image plane IMP and may be between about 1 millimeter and about 20 millimeters.
- a photo detector 170 e.g., camera or a rotating slit
- the captured image(s) can be analyzed, e.g., via a computer 174 that is operably connected to photodetector 170 .
- the computer 174 can be used to analyze and display information about the captured image spot(s) 110 .
- a plurality of image spots 110 are detected and compared to a reference spot (e.g., as obtained via optical modeling based on the design of the optical probe 10 ) to assess performance.
- the mode field diameter MFD is a measure of the spot size or beam width of light propagating in a single mode fiber or at another location in an optical system.
- the mode field diameter MFD within an optical fiber is a function of the source wavelength, fiber core radius and fiber refractive index profile.
- the optical probe 10 is capable of producing an image spot 110 having a mode field diameter MFD of between about 30 microns to about 100 microns at a 1/e 2 threshold at the image plane IMP.
- An exemplary mode field diameter of the optical fiber 18 may be 9.2 microns at a 1/e 2 threshold.
- the mode field diameter MFD may be sensed as an indicator of the quality of the image spot 110 .
- the position of optical fiber 18 can be axially adjusted within the alignment feature 22 (e.g., the first and second v-shaped grooves 80 , 84 ) based on making one or more measurements of image spot 110 until an acceptable or optimum image spot 110 is formed.
- the one or more measured image spots 110 are compared to a reference image spot or a reference image spot size.
- the optical fiber 18 can then be fixed in its aligned position within the alignment feature 22 .
- the coated portion 36 of optical fiber 18 can be fixed (e.g., bonded) within the first v-shaped groove 80 to provide strain relief.
- the beam-shaping element 26 has an X-axis radius of curvature of about 1.16 millimeters corresponding to a conic constant of about 0.5858 and a Y-axis radius of curvature of about 1.2935 millimeters corresponding to a conic constant of about 0.8235. Further, the conic shape of the beam-shaping element 26 is decentered along the Y-axis by about 0.7 millimeters, decentered along the Z-axis by about 0.089 millimeters, and has a rotation between the Y- and Z-axes of about 89.7°.
- the distance D 1 between the fiber end 40 and reflective surface 100 is about 1.314 millimeters.
- Such an optical probe is capable of forming the image spot 110 at a working distance D 2 of about 9.0 millimeters with a mode field diameter MFD of about 64 microns at the 1/e 2 threshold.
- optical probe 10 and the exemplary optical coherence tomography alignment system 150 has a monolithic beam-shaping body 14 which defines a reflective beam-shaping element 26 , the system has no need for the use of spacers, GRIN lenses or refractive elements such as lenses. Further, eliminating the use of multiple optical components is beneficial because there are fewer material interfaces which may result in optical back reflections or vignetting of the image spot 110 . Additionally, by shaping the beam 42 into the image spot 110 solely based on reflection, higher power light sources may be used than conventional optical probes. Optical probes utilizing polymers as a refractive element are limited in the intensity of light they may refract; however, reflective systems do not have such limitations.
- the optical probe 10 uses a single reflective beam-shaping element 26 defined by the monolithic beam-shaping body 14 , in contrast to a multi-component system, differences in the coefficient of thermal expansion between different components do not exist. For example, in prior art designs, lenses and reflective surfaces may come out of alignment due to a temperature differential between the operating temperature and the temperature at which the probe was calibrated and/or assembled. In the monolithic, single reflective surface design of the present disclosure, this is less likely to happen due to all components having the same coefficient of thermal expansion because all components are composed of the same material. Additionally, due to the simplistic design of the present disclosure, the manufacturing of the optical probe 10 is simplified and therefore less expensive to make.
- FIG. 4 illustrates an exemplary OCT system 200 that includes an embodiment of the optical probe 10 as disclosed herein.
- OCT system 200 includes a light source 194 and an interferometer 190 .
- the light source 194 is optically connected to a fiber optic coupler (“coupler”) 198 via a first optical fiber section FI.
- OCT probe 10 is optically connected to coupler 198 via optical fiber 18 and constitutes the sample arm SA of the interferometer 190 .
- OCT system 200 also includes a movable mirror system 202 optically connected to coupler 198 via an optical fiber section F 2 .
- Mirror system 202 and optical fiber section F 2 constitute a reference arm RA of the interferometer 190 .
- Mirror system 202 is configured to alter the length of the reference arm, e.g., via a movable mirror (not shown).
- OCT system 200 further includes the photodetector 170 optically coupled to coupler 198 via a third optical fiber section F 3 .
- Photodetector 170 in turn is electrically connected to computer 174 .
- light source 194 generates light 206 that travels to interferometer 190 over optical fiber section FI.
- the light 206 is divided by coupler 198 into light 206 RA that travels in reference arm RA and light 206 SA that travels in sample arm SA.
- the light 206 RA that travels in reference arm RA is reflected by mirror system 202 and returns to coupler 198 , which directs the light to photo detector 170 .
- the light 206 SA that travels in sample arm SA is processed by optical probe 10 as described above (where this light was referred to as just emitted beam 42 ) to form image spot 162 on or in a sample 210 .
- the resulting scattered light is collected by optical probe 10 and directed through optical fiber 18 to coupler 198 , which directs it (as light 206 SA) to photo detector 170 .
- the reference arm light 206 RA and sample arm light 206 SA interfere and the interfered light is detected by photodetector 170 .
- Photodetector 170 generates an electrical signal SI in response thereto, which is then sent to computer 174 for processing using standard OCT signal processing techniques.
- the optical interference of light 206 SA from sample arm SA and light 206 RA from reference arm RA is detected by photodetector 170 only when the optical path difference between the two arms is within the coherence length of light 206 from light source 194 .
- Depth information from sample 210 is acquired by axially varying the optical path length of reference arm RA via mirror system 202 and detecting the interference between light from the reference arm and scattered light from the sample arm that originates from within the sample.
- a three-dimensional image is obtained by transversely scanning in two dimensions the optical path in the sample arm SA. The axial resolution of the process is determined by the coherence length.
- optical probe 10 may be used in a wide variety of applications, including other OCT techniques (e.g., Frequency Domain OCT, Spectral Domain OCT).
- OCT techniques e.g., Frequency Domain OCT, Spectral Domain OCT.
- the term “coupled” in all of its forms, couple, coupling, coupled, etc. generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.
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Abstract
Description
- This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 62/101,105 filed on Jan. 8, 2015, the content of which is relied upon and incorporated herein by reference in its entirety.
- The present disclosure relates to optical coherence tomography, and in particular to a monolithic beam-shaping optical probe for an optical coherence tomography probe.
- Optical coherence tomography (OCT) is used to capture a high-resolution cross-sectional image of biological tissues and is based on fiber-optic interferometry. The core of an OCT system is a Michelson interferometer, which typically includes a first optical fiber which is used as a reference arm and a second optical fiber which is used as a sample arm. The sample arm includes the sample to be analyzed, as well as a probe that contains optical components therein. A light source upstream of the probe provides light used in imaging. A photodetector is arranged in the optical path downstream of the sample and reference arms. The probe is used to direct light into or onto the sample and then to collect scattered light from the sample.
- Optical interference of light from the sample arm and the reference arm is detected by the photodetector only when the optical path difference between the two arms is within the coherence length of the light from the light source. Depth information from the sample is acquired by axially varying the optical path length of the reference arm and detecting the interference between light from the reference arm and scattered light from the sample arm. A three-dimensional image is obtained by transversely scanning in two dimensions the optical path in the sample arm. The axial/depth resolution of the process is determined by the coherence length, while the overall transverse resolution is dictated by the size of the image spot formed by the optical components of the probe.
- Because the probe typically needs to be inserted into a small cavity of the body, it must be small and preferably have a simple optical design. Exemplary designs for the probe include a transparent cylinder in which the miniature probe optical components are contained and through which light is transmitted and received. However, light may be lost due to back reflection when it passes through materials having a different refractive index, thus decreasing image spot intensity. Additionally, back reflections decrease the signal to noise ratio in the data. Moreover, having multiple and separate optical components in the probe is generally problematic because the small optical components have to be assembled and aligned, which adds to the cost and complexity of manufacturing the probe.
- According to one embodiment of the present disclosure, a beam-shaping optical system suitable for use with optical coherence tomography includes a beam-shaping body having a beam-shaping element and an alignment feature. An optical fiber is coupled to the alignment feature. The fiber has a fiber end configured to emit an electromagnetic beam. The fiber and the body are configured to direct the beam into the beam-shaping element such that the beam is shaped into an image spot solely by reflection from the beam-shaping element.
- According to another embodiment of this disclosure, an optical coherence tomography probe includes a beam-shaping body integrally defining an alignment feature and a beam-shaping element, the beam-shaping element being an external surface of the beam-shaping body. An optical fiber is coupled to the alignment feature, the fiber having a fiber end configured to emit a beam. The fiber and the body are configured to direct the beam into the beam-shaping element such that the beam is shaped externally of the beam-shaping body.
- According to a further embodiment of this disclosure, a method of forming an image spot for optical coherence tomography using an optical fiber includes steps of supporting an optical fiber in an alignment feature of a beam-shaping body having a beam-shaping element, transmitting an electromagnetic beam from the optical fiber into the beam-shaping element, and shaping the beam with the beam-shaping element solely by reflection into the image spot
- Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
- It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments, and together with the description serve to explain principles and operation of the various embodiments.
-
FIG. 1 is an elevated exploded view of an optical probe for use in OCT according to one embodiment; -
FIG. 2A is a cross-sectional view of the optical probe depicted inFIG. 1 in assembly taken along line II-II according to one embodiment; -
FIG. 2B is a cross-sectional view of the optical probe depicted inFIG. 1 in assembly taken along line II-II according to an alternative embodiment; -
FIG. 3 is a schematic diagram of an OCT alignment system that includes the optical probe according to one embodiment; and -
FIG. 4 is a schematic diagram of an OCT system that includes an optical probe according to one embodiment. - Reference will now be made in detail to the present preferred embodiments, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.
- For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivates thereof shall relate to an
optical probe 10 as oriented inFIG. 1 , unless stated otherwise. However, it is to be understood that theoptical probe 10 may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. - Depicted in
FIGS. 1-3 is an embodiment of the beam-shapingoptical probe 10 suitable for use in OCT and the making of OCT images. Theoptical probe 10 includes a beam-shapingbody 14 to which anoptical fiber 18 may be coupled. The beam-shapingbody 14 integrally defines analignment feature 22 and a beam-shapingelement 26. Theoptical fiber 18 has acentral axis 28 and includes acladding 30, acore 32, and acoating 34. In various embodiments thecoating 34 is polymeric. In the depicted embodiments, a section of thecoating 34 is stripped from theoptical fiber 18 to form a coatedportion 36 and anuncoated portion 38. Theuncoated portion 38 includes afiber end 40 configured to emit anelectromagnetic beam 42. Theelectromagnetic beam 42 is emitted along an optical axis OA defined by the beam-shapingbody 14. In operation, theoptical fiber 18 is coupled to thealignment feature 22. In the depicted embodiment, the beam-shapingbody 14 is monolithic and integrally defines the beam-shapingelement 26 and thealignment feature 22. - Referring now to
FIG. 1 , in the depicted embodiment, the beam-shapingbody 14 includes afront end 44, aback end 46, and anexternal surface 48. Although the beam-shapingbody 14 is monolithic, for convenience, the beam-shapingbody 14 can be considered to be three main sections, namely afront section 60adjacent front end 44 and the beam-shapingelement 26, acentral section 64 in between thefront end 44 and backend 46, and aback section 68 adjacent theback end 46 and the alignment feature 22. - In various embodiments, the beam-shaping
body 14 includes a polymeric composition. Exemplary polymeric materials for the beam-shapingbody 14 include ZEONOR® (available from Zeon Chemicals L.P., Louisville, Ky.), polyetherimide (PEI), polyethylene, polypropylene, polycarbonate, engineered polymers (e.g., liquid crystal), as well as any other polymeric material or combination of polymeric materials capable of forming the beam-shapingbody 14 and producing a smooth surface. In other embodiments, the beam-shapingbody 14 may include metals, ceramics, or composites thereof. The beam-shapingbody 14 is capable of formation by conventional manufacturing techniques such as injection molding, casting, machining, thermoforming, or extrusion. - In the depicted embodiment the
external surface 48 of theback section 68 includes a firstflat surface 72 and a secondflat surface 76, the alignment feature 22 integrally formed therein. While the beam-shapingbody 14 is depicted with the firstflat surface 72 elevated relative to the secondflat surface 76, various embodiments allow for theflat surfaces flat surface 76 may be elevated above the firstflat surface 72. In the depicted embodiment, thealignment feature 22 includes a first v-shapedgroove 80 located in the firstflat surface 72 and a second v-shapedgroove 84 located in the secondflat surface 76. The second v-shapedgroove 84 is open to and aligned with the first v-shapedgroove 80. It should be understood that thealignment feature 22 may additionally or alternatively incorporate grooves or trenches which are generally circular, square, u-shaped or other shapes operable to couple with theoptical fiber 18. In the depicted embodiment, the first and second v-shapedgrooves groove 80 having a greater depth and higher pitch than the second v-shapedgroove 84. - The differing depths and pitches of the first and second v-shaped
grooves uncoated portions optical fiber 18 to be coupled to the beam-shapingbody 14 while allowing thecentral axis 28 of theoptical fiber 18 to align substantially coaxial with the optical axis OA of the beam-shapingbody 14. Additionally, the differing depths and pitches of the first and second v-shapedgrooves alignment feature edge 88 between the first and second v-shapedgrooves portion 36 of theoptical fiber 18 butts whenoptical fiber 18 is coupled in the first and second v-shapedgrooves alignment feature edge 88 assists in properly aligning theoptical fiber 18 with the beam-shapingbody 14 and also serves to keep theoptical fiber 18 in place within the first and second v-shapedgrooves alignment feature 22 may incorporate a stepped aperture allowing insertion of theoptical fiber 18 into the beam-shapingbody 14, or other features, for joining thefiber 18 to theback section 68 of thebody 14. - In the depicted embodiment, the
central section 64 of the beam-shapingbody 14 is thinner than theback section 68 and thefront section 60. Thecentral section 64 of theexterior surface 48 defines acentral surface 90 and anair gap 94. Thecentral surface 90 of thecentral section 64 extends beneath the optical axis OA of the beam-shapingbody 14 between thefront section 60 and theback section 68. Theair gap 94 allows thefiber end 40 of theoptical fiber 18 to extend into thecentral section 64 above the central surface 90 (FIG. 2A ). - Still referring to
FIG. 1 , the beam-shapingelement 26 is integrally defined by thefront section 60 of the beam-shapingbody 14. Thefront section 60 of the beam-shapingbody 14 extends in an upwardly and inwardly curved manner from thecentral surface 90 to define the beam-shapingelement 26. The beam-shapingelement 26 is substantially conic in shape and curves inwardly toward the optical axis OA of the beam-shapingbody 14. The conic shape of the beam-shapingelement 26 is defined by a radius of curvature along an X-axis and a Y-axis of the beam-shapingbody 14. - In order to properly shape the
beam 42, the beam-shapingelement 26 may have a radius of curvature along the X-axis that is the same or different than a radius of curvature in the Y-axis. The radius of curvature of the X- and Y-axes of the beam-shapingelement 26 may have an absolute value of between about 0.5 millimeters and about 10 millimeters, and more specifically, about 1.0 millimeter to about 4.0 millimeters. The conic constant of the X- and Y-axes of the beam-shapingelement 26 may independently range from about 1 to about −2, and more specifically between about 0 and about −1. It should be understood that the radii and conic constants of the curvature explained above describe the overall shape of the beam-shapingelement 26, and do not necessarily reflect local radii or conic constants of the beam-shapingelement 26. The radius of curvature of the X-axis and Y-axis of the beam-shapingelement 26 may be adjusted independently in order to correct for any transparent housings or sheaths disposed around theoptical probe 10. The conic shape of the beam-shapingelement 26 may be decentered along the Y- or Z-axes between about 0.01 millimeters and about 0.8 millimeters. Additionally, the conic shape of the beam-shapingelement 26 may have a rotation between the Y- and Z-axes of between about 70° and 120°. - The beam-shaping
element 26 is configured to collect and shape (e.g., collimate, converge, and/or change the optical path of) through reflection the electromagnetic beam 42 (FIG. 2A ) emitted from theoptical fiber 26, as explained in greater detail below. Positioned on the beam-shapingelement 26 is areflective coating 100.Reflective coating 100 may be a dielectric coating, a metal coating, or an enhanced metal coating. Exemplary metal coatings include silver, gold, aluminum, and other lustrous metals capable of reflecting thebeam 42. Dielectric materials may include SiO2, TiO2 and combinations thereof. Further, enhanced metal coatings may include a combination of one or more of the previously described metals and/or dielectrics. Thereflective coating 100 may also include a capping layer to protect it from environmental conditions (e.g., water, oxygen, and/or sterilization procedures) as well as an adhesion layer to bond thereflective surface 100 to the beam-shapingbody 14. Thereflective coating 100 is positioned on the beam-shapingelement 26 such that the emittedbeam 42 is reflected externally to the beam-shapingbody 14, and not within it. - Referring now to
FIGS. 2A-3 , theoptical fiber 18 is depicted as protruding from theback section 68 into theair gap 94 above thecentral surface 90 of thecentral section 64. In operation, theoptical fiber 18 is configured to act as a wave guide for electromagnetic radiation, specifically light at an operating wavelength λ. Theoptical fiber 18 carries light from an upstream light source (not shown) to thefiber end 40 where the light is emitted as theelectromagnetic beam 42. In one embodiment, the operating wavelength λ includes an infrared wavelength such as one in the range from about 850 nanometers to about 1,600 nanometers, with exemplary operating wavelengths λ being about 1300 nanometers and about 1560 nanometers. - The
optical fiber 18 and thealignment feature 22 of the beam-shapingbody 14 are configured to couple such that theelectromagnetic beam 42 is emitted from thefiber end 40 on an optical path OP that is both substantially coaxial with the optical axis OA of the beam-shapingbody 14, and directed toward the beam-shapingelement 26. As thebeam 42 is emitted from thefiber end 40, it propagates through theair gap 94 and the diameter of the optical path OP widens with increasing distance from thefiber end 40. A distance D1 between thefiber end 40 and thereflective surface 100 is set based on a desired size of abeam spot 104. Thebeam spot 104 is the area of light thebeam 42 forms as it strikes the beam-shapingelement 26. Thebeam spot 104 grows in diameter with increasing distance from thefiber end 40. In order for the beam-shapingelement 26 to properly shape thebeam 42, thebeam spot 104 must be have the proper diameter when contacting the reflective surface 100 (e.g., approximately half the diameter of the reflective surface 100). Accordingly, thefiber end 40 must be placed a predetermined distance from the beam-shapingelement 26 for thebeam 42 to be properly shaped. In various embodiments, the distance D1 between thefiber end 40 and thereflective surface 100 may range between about 0.2 millimeters and about 2.6 millimeters. In one embodiment, the distance D1 is about 1.314 millimeters. The diameter of thebeam spot 104 may range from about 200 microns to about 800 microns and more specifically, between about 400 microns to about 600 microns. - As the
beam 42 enters the beam-shapingelement 26, its optical path OP is folded by an angle β from reflection off of thereflective coating 100. In the depicted embodiment, the angle β is approximately 90°, but in various embodiments can vary by greater than or less than 10° on either side of 90°. The radius of curvature and position of the beam-shapingelement 26 determine both the angle β that the optical path OP ofbeam 42 will be folded by, and also a working distance D2 to an image plane IMP where thebeam 42 converges to form animage spot 110. Accordingly, the emittedbeam 42 is shaped into theimage spot 110 solely by reflection from the beam-shapingelement 26. - Referring now to
FIG. 2A , in various examples the beam-shapingbody 14 has an axial length L1 in the range from about 5.0 millimeters to about 10.0 millimeters, backsection 68 has a length along the optical axis OA in the range of about 2.0 millimeters to about 5.0 millimeters, and thecentral section 64 has a length of about 0.2 millimeters to about 2.3 millimeters. Further in the various examples,front section 60 has a length in the range from 0.5 millimeters to 2.0 millimeters. Also, the beam-shapingbody 14 has width W1 at backsection 68 that can be in the range from 0.3 millimeters to 1.0 millimeters, and has a width W2 atfront section 60 that can be in the range from 0.5 millimeters to 2.0 millimeters. The values for these parameters are exemplary and other values and ranges are possible, depending on the particular application. - The
fiber end 40 of theoptical fiber 18 may be cleaved at an angle in order to prevent undesired back reflection of light into thefiber 18. OCT is particularly sensitive to back reflections of light which have not been scattered off of a sample to be tested (i.e., reflections from theoptical probe 10 or refractive surfaces along the optical path OP). The back reflected light may lead to distortion in the OCT image because of increased noise and artifacts. Cleaving thefiber end 40 at an angle minimizes the coupling of the back reflected light back into theoptical fiber 18. Thefiber end 40 may be cleaved at an angle between about 0° to about 10°, and more particularly between about 6° to 9°. In some embodiments, thealignment feature 22 may be angled with respect to the optical axis OA of theoptical probe 10 in order to compensate for the cleavedfiber end 40. The angledalignment feature 22 would keep the optical path OP of thebeam 42 substantially coaxial with the optical axis OA of theoptical probe 10. Additionally or alternatively, thefiber end 40 may include an anti-reflection film to reduce the amount of reflected light absorbed by theoptical fiber 18. The anti-reflection film may include a single or multilayer dielectric material configured to cancel light reflected back to theoptical probe 10. - Referring now to
FIG. 2B , thefiber end 40 of theoptical fiber 18 may also be ball-terminated. According to one embodiment, ball-termination of theoptical fiber 18 may be achieved by placing thefiber end 40 between a pair of arc electrodes. The arc electrodes melt thecladding 30 andcore 32 of theoptical fiber 18. Surface tension of the meltedoptical fiber 18 forms a substantially spherical ball on thefiber end 40 which then cools and hardens. Theelectromagnetic beam 42 may be emitted from the ball-termination fiber end 40. The ball-termination of thefiber end 40 may have a diameter of between about 100 microns to about 600 microns, and more specifically between about 200 microns to about 500 microns. - Similarly to the cleaved
fiber end 40 ofFIG. 2A , ball-termination of thefiber end 40 of theoptical fiber 18 prevents the collection of back reflected light, and thus minimizes distortion of OCT images. Advantageously, ball-termination of thefiber end 40 causes the optical path OP of the emittedbeam 42 to diverge faster than the cleavedfiber end 40 as it propagates through the air gap 94 (i.e. the diameter of thebeam spot 104 increases faster). Because the optical path OP diverges faster from the ball-terminatedfiber end 40, the desiredbeam spot 104 size may be achieved with a shorter distance D1 between thefiber end 40 and the beam-shapingelement 26. This effectively allows the axial length L1 of theoptical probe 10 to be shortened compared to embodiments having a cleavedfiber end 40. Similarly to the cleavedfiber end 40 ofFIG. 2A , the ball-terminatedfiber end 40 ofFIG. 2B may include an anti-reflection film. - In an exemplary method for forming an
image spot 110 for use in OCT, a first step of supporting anoptical fiber 18 in analignment feature 22 of a beam-shapingbody 14 having a beam-shapingelement 26 is performed. Next, a step of transmitting anelectromagnetic beam 42 from theoptical fiber 18 into the beam-shapingelement 26 is performed. Finally, a step of shaping thebeam 42 with the beam-shapingelement 26 solely by reflection into theimage spot 110 is performed. - Referring now to
FIG. 3 , theoptical probe 10 is depicted in use within anOCT alignment system 150. As explained above, light traveling within theoptical fiber 18 exits thefiber end 40 and is emitted asbeam 42 along the optical axis OA. The optical path OP of thebeam 42 diverges as it passes through theair gap 94 until it enters the beam-shapingelement 26 and reflects from thereflective surface 100. The curvature of the beam-shapingelement 26 causes the light to converge uniformly toimage point 110 due to the beam-shapingelement 26 surface being conic. In the depicted embodiment, as thebeam 42 converges, it passes through a portion of ahousing 158 which may act as a protective sheath for theoptical probe 10. In other embodiments, theoptical probe 10 may be used with the optical coherencetomography alignment system 150 without any housing or protective covering. As thebeam 42 converges, it forms theimage spot 110 at the image plane IMP. The working distance D2 is measured between the horizontal portion of the optical axis OA of the probe and the image plane IMP and may be between about 1 millimeter and about 20 millimeters. - The proper alignment of the
optical fiber 18 within beam-shapingbody 14 when formingprobe 10 is facilitated by the use of thealignment feature 22 and theOCT alignment system 150. In an exemplary method for alignment of theoptical fiber 18, a photo detector 170 (e.g., camera or a rotating slit) can be used to capture at least one image ofimage spot 110 and generate a detector signal SD representative of the captured image. The captured image(s) can be analyzed, e.g., via acomputer 174 that is operably connected tophotodetector 170. Thecomputer 174 can be used to analyze and display information about the captured image spot(s) 110. In an example, a plurality of image spots 110 are detected and compared to a reference spot (e.g., as obtained via optical modeling based on the design of the optical probe 10) to assess performance. - The mode field diameter MFD is a measure of the spot size or beam width of light propagating in a single mode fiber or at another location in an optical system. The mode field diameter MFD within an optical fiber is a function of the source wavelength, fiber core radius and fiber refractive index profile. In the depicted embodiment, the
optical probe 10 is capable of producing animage spot 110 having a mode field diameter MFD of between about 30 microns to about 100 microns at a 1/e2 threshold at the image plane IMP. An exemplary mode field diameter of theoptical fiber 18 may be 9.2 microns at a 1/e2 threshold. The mode field diameter MFD may be sensed as an indicator of the quality of theimage spot 110. - The position of
optical fiber 18 can be axially adjusted within the alignment feature 22 (e.g., the first and second v-shapedgrooves 80, 84) based on making one or more measurements ofimage spot 110 until an acceptable oroptimum image spot 110 is formed. In an example, the one or more measured image spots 110 are compared to a reference image spot or a reference image spot size. Theoptical fiber 18 can then be fixed in its aligned position within thealignment feature 22. In an example, the coatedportion 36 ofoptical fiber 18 can be fixed (e.g., bonded) within the first v-shapedgroove 80 to provide strain relief. - In an exemplary embodiment of
optical probe 10, the beam-shapingelement 26 has an X-axis radius of curvature of about 1.16 millimeters corresponding to a conic constant of about 0.5858 and a Y-axis radius of curvature of about 1.2935 millimeters corresponding to a conic constant of about 0.8235. Further, the conic shape of the beam-shapingelement 26 is decentered along the Y-axis by about 0.7 millimeters, decentered along the Z-axis by about 0.089 millimeters, and has a rotation between the Y- and Z-axes of about 89.7°. The distance D1 between thefiber end 40 andreflective surface 100 is about 1.314 millimeters. Such an optical probe is capable of forming theimage spot 110 at a working distance D2 of about 9.0 millimeters with a mode field diameter MFD of about 64 microns at the 1/e2 threshold. - Because
optical probe 10 and the exemplary optical coherencetomography alignment system 150 has a monolithic beam-shapingbody 14 which defines a reflective beam-shapingelement 26, the system has no need for the use of spacers, GRIN lenses or refractive elements such as lenses. Further, eliminating the use of multiple optical components is beneficial because there are fewer material interfaces which may result in optical back reflections or vignetting of theimage spot 110. Additionally, by shaping thebeam 42 into theimage spot 110 solely based on reflection, higher power light sources may be used than conventional optical probes. Optical probes utilizing polymers as a refractive element are limited in the intensity of light they may refract; however, reflective systems do not have such limitations. - Moreover, because the
optical probe 10 uses a single reflective beam-shapingelement 26 defined by the monolithic beam-shapingbody 14, in contrast to a multi-component system, differences in the coefficient of thermal expansion between different components do not exist. For example, in prior art designs, lenses and reflective surfaces may come out of alignment due to a temperature differential between the operating temperature and the temperature at which the probe was calibrated and/or assembled. In the monolithic, single reflective surface design of the present disclosure, this is less likely to happen due to all components having the same coefficient of thermal expansion because all components are composed of the same material. Additionally, due to the simplistic design of the present disclosure, the manufacturing of theoptical probe 10 is simplified and therefore less expensive to make. -
FIG. 4 illustrates anexemplary OCT system 200 that includes an embodiment of theoptical probe 10 as disclosed herein.OCT system 200 includes alight source 194 and aninterferometer 190. Thelight source 194 is optically connected to a fiber optic coupler (“coupler”) 198 via a first optical fiber section FI.OCT probe 10 is optically connected to coupler 198 viaoptical fiber 18 and constitutes the sample arm SA of theinterferometer 190.OCT system 200 also includes amovable mirror system 202 optically connected to coupler 198 via an optical fiber section F2.Mirror system 202 and optical fiber section F2 constitute a reference arm RA of theinterferometer 190.Mirror system 202 is configured to alter the length of the reference arm, e.g., via a movable mirror (not shown).OCT system 200 further includes thephotodetector 170 optically coupled tocoupler 198 via a third optical fiber section F3.Photodetector 170 in turn is electrically connected tocomputer 174. - In operation,
light source 194 generates light 206 that travels to interferometer 190 over optical fiber section FI. The light 206 is divided bycoupler 198 into light 206RA that travels in reference arm RA and light 206SA that travels in sample arm SA. The light 206RA that travels in reference arm RA is reflected bymirror system 202 and returns to coupler 198, which directs the light tophoto detector 170. The light 206SA that travels in sample arm SA is processed byoptical probe 10 as described above (where this light was referred to as just emitted beam 42) to form image spot 162 on or in asample 210. The resulting scattered light is collected byoptical probe 10 and directed throughoptical fiber 18 tocoupler 198, which directs it (as light 206SA) tophoto detector 170. The reference arm light 206RA and sample arm light 206SA interfere and the interfered light is detected byphotodetector 170.Photodetector 170 generates an electrical signal SI in response thereto, which is then sent tocomputer 174 for processing using standard OCT signal processing techniques. - The optical interference of light 206SA from sample arm SA and light 206RA from reference arm RA is detected by
photodetector 170 only when the optical path difference between the two arms is within the coherence length of light 206 fromlight source 194. Depth information fromsample 210 is acquired by axially varying the optical path length of reference arm RA viamirror system 202 and detecting the interference between light from the reference arm and scattered light from the sample arm that originates from within the sample. A three-dimensional image is obtained by transversely scanning in two dimensions the optical path in the sample arm SA. The axial resolution of the process is determined by the coherence length. - It should be understood that although the use of the
optical probe 10 was described in connection with only one OCT technique, theoptical probe 10 may be used in a wide variety of applications, including other OCT techniques (e.g., Frequency Domain OCT, Spectral Domain OCT). - While the embodiments disclosed herein have been set forth for the purpose of illustration, the foregoing description should not be deemed to be a limitation on the scope of the disclosure or the appended claims. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claims.
- It will be understood by one having ordinary skill in the art that construction of the described invention and other components is not limited to any specific material. Other exemplary embodiments of the invention disclosed herein may be formed from a wide variety of materials, unless described otherwise herein. In this specification and the amended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise.
- Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of that range, and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.
- For purposes of this disclosure, the term “coupled” (in all of its forms, couple, coupling, coupled, etc.) generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.
- It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claims.
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---|---|---|---|---|
CN107949311B (en) | 2015-04-16 | 2021-04-16 | Gentuity有限责任公司 | Low-light level probe for neurology |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130266259A1 (en) * | 2012-03-28 | 2013-10-10 | Corning Incorporated | Monolithic beam-shaping optical systems and methods for an oct probe |
US20130322818A1 (en) * | 2012-03-05 | 2013-12-05 | Nanoprecision Products, Inc. | Coupling device having a structured reflective surface for coupling input/output of an optical fiber |
US20140066756A1 (en) * | 2012-09-04 | 2014-03-06 | Ninepoint Medical, Inc. | Low cost molded optical probe with astigmatic correction, fiber port, low back reflection, and highly reproducible in manufacturing quantities |
US8675293B2 (en) * | 2010-01-25 | 2014-03-18 | Axsun Technologies, Inc. | SOI lens structure for medical probe |
US20140340756A1 (en) * | 2013-05-17 | 2014-11-20 | Ninepoint Medical, Inc. | Optical coherence tomography optical probe systems and methods to reduce artifacts |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6904197B2 (en) | 2002-03-04 | 2005-06-07 | Corning Incorporated | Beam bending apparatus and method of manufacture |
US7289701B2 (en) * | 2002-03-14 | 2007-10-30 | Sae Magnetics (Hong Kong) Limited | Integrated platform for passive optical alignment of semiconductor device with optical fiber |
US6891984B2 (en) | 2002-07-25 | 2005-05-10 | Lightlab Imaging, Llc | Scanning miniature optical probes with optical distortion correction and rotational control |
JP4181519B2 (en) * | 2004-03-23 | 2008-11-19 | 日本電信電話株式会社 | Optical multiplexer / demultiplexer |
WO2006037132A1 (en) * | 2004-09-29 | 2006-04-06 | The General Hospital Corporation | System and method for optical coherence imaging |
WO2008137710A1 (en) | 2007-05-03 | 2008-11-13 | University Of Washington | High resolution optical coherence tomography based imaging for intraluminal and interstitial use implemented with a reduced form factor |
US8582934B2 (en) * | 2007-11-12 | 2013-11-12 | Lightlab Imaging, Inc. | Miniature optical elements for fiber-optic beam shaping |
JP2009201969A (en) * | 2008-02-01 | 2009-09-10 | Fujifilm Corp | Oct optical probe and optical tomography imaging apparatus |
JP2010142422A (en) * | 2008-12-18 | 2010-07-01 | Fujifilm Corp | Optical probe and optical observation apparatus |
JP2011127924A (en) * | 2009-12-15 | 2011-06-30 | Sun Tec Kk | Imaging probe |
US8515221B2 (en) | 2010-01-25 | 2013-08-20 | Axsun Technologies, Inc. | Silicon optical bench OCT probe for medical imaging |
EP2528495B1 (en) * | 2010-01-25 | 2018-03-28 | Axsun Technologies, Inc. | Silicon optical bench oct probe for medical imaging |
-
2016
- 2016-01-06 US US14/989,261 patent/US10162114B2/en not_active Expired - Fee Related
- 2016-01-08 JP JP2017536536A patent/JP2018507400A/en active Pending
- 2016-01-08 WO PCT/US2016/012558 patent/WO2016112235A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8675293B2 (en) * | 2010-01-25 | 2014-03-18 | Axsun Technologies, Inc. | SOI lens structure for medical probe |
US20130322818A1 (en) * | 2012-03-05 | 2013-12-05 | Nanoprecision Products, Inc. | Coupling device having a structured reflective surface for coupling input/output of an optical fiber |
US20130266259A1 (en) * | 2012-03-28 | 2013-10-10 | Corning Incorporated | Monolithic beam-shaping optical systems and methods for an oct probe |
US20140066756A1 (en) * | 2012-09-04 | 2014-03-06 | Ninepoint Medical, Inc. | Low cost molded optical probe with astigmatic correction, fiber port, low back reflection, and highly reproducible in manufacturing quantities |
US20140340756A1 (en) * | 2013-05-17 | 2014-11-20 | Ninepoint Medical, Inc. | Optical coherence tomography optical probe systems and methods to reduce artifacts |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160070070A1 (en) * | 2014-09-09 | 2016-03-10 | Corning Incorporated | Integrated torque assembly and methods for oct using an optical fiber cable |
US11064873B2 (en) | 2015-08-31 | 2021-07-20 | Gentuity, Llc | Imaging system includes imaging probe and delivery devices |
US11583172B2 (en) | 2015-08-31 | 2023-02-21 | Gentuity, Llc | Imaging system includes imaging probe and delivery devices |
US11937786B2 (en) | 2015-08-31 | 2024-03-26 | Gentuity, Llc | Imaging system includes imaging probe and delivery devices |
US11684242B2 (en) | 2017-11-28 | 2023-06-27 | Gentuity, Llc | Imaging system |
CN112612082A (en) * | 2019-10-04 | 2021-04-06 | 日本麦可罗尼克斯股份有限公司 | Optical probe, optical probe array, inspection system, and inspection method |
US11583169B2 (en) * | 2019-12-23 | 2023-02-21 | Industrial Technology Research Institute | Optical fiber scanning probe and endoscope having the same |
Also Published As
Publication number | Publication date |
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US10162114B2 (en) | 2018-12-25 |
JP2018507400A (en) | 2018-03-15 |
WO2016112235A1 (en) | 2016-07-14 |
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